Low temperature gas generating compositions

ABSTRACT

A pyrotechnic powder composition comprising a mixture of an oxidizer compound containing oxygen and a metal selected from the group consisting of sodium, potassium, lithium, barium, magnesium and calcium, and an oxygen bearing metal organic compound is used for inflating a passenger restraint bag for an automobile. The compounds are selected so that a stoichiometric reaction between the oxidizer and the oxygen bearing metal organic compound yields carbon dioxide and water vapor and at least a binary mixture of metal salts having a melting point substantially below the melting point of any of the resultant metal salts alone, and having net heat of reaction less than about 1,000 calories per gram of pyrotechnic composition. One preferred composition comprises about 35 percent sodium formate and 65 percent potassium chlorate, for example. When these react the low melting slag of potassium chloride and sodium oxide collects on cooler surfaces of the gas generator thereby reducing heat input to the inflatable bag and substantially preventing formation of smoke.

United States Patent Catanzarite Oct. 7, 1975 [75] Inventor: VincentOwen Catanzarite, Las

Vegas, Nev.

[73] Assignee: Specialty Products Development Corporation, Medina, OhioNotice: The portion of the term of this patent subsequent to Sept. 21,1991, has been disclaimed.

[22] Filed: Oct. 17, 1973 [21] App]. No.: 407,269

Related U.S. Application Data [63] Continuation-impart of Ser. No.234,312, March 13, 1972, abandoned.

[52] U.S. Cl. 149/83; 149/75; 149/76 [51] Int. Cl. C06B 29/08 [58] Fieldof Search l4 9/75, 76, 83

[56] References Cited UNITED STATES PATENTS 3,837,942 9/1974 Catanzaritel49/83 Primary Examiner-Stephen J. Lechert, Jr. Attorney, Agent, orFirmChristie, Parker & Hale [5 7] ABSTRACT A pyrotechnic powdercomposition comprising a mixture of an oxidizer compound containingoxygen and a metal selected from the group consisting of sodium,potassium, lithium, barium, magnesium and calcium, and an oxygen bearingmetal organic compound is used for inflating a passenger restraint bagfor an automobile. The compounds are selected so that a stoichiometricreaction between the oxidizer and the oxygen bearing metal organiccompound yields carbon dioxide and water vapor and at least a binarymixture of metal salts having a melting point substantially below themelting point of any of the resultant metal salts alone, and having netheat of reaction less than about 1,000 calories per gram of pyrotechniccomposition. One preferred composition comprises about 35 percent sodiumformate and 65 percent potassium chlorate, for example. When these reactthe low melting slag of potassium chloride and sodium oxide collects oncooler surfaces of the gas generator thereby reducing heat input to theinflatable bag and substantially preventing formation of smoke.

14 Claims, No Drawings LOW TEMPERATURE GAS GENERATING COMPOSITIONS BACKGROUND This is a continuation in part of my application Ser. No.234,312, filed Mar. 13, 1972, now abandoned.

Governmental requirements for automobile passenger restraint systemsinclude an inflatable bag that momentarily and temporarily restrains apassenger during the critical instant of a collision impact. For safeand successful use, the bag must be inflated in very short time andthereafter deflated to release the passenger. The gas used to inflatethe bag must be cool enough to avoid damage to the bag and injury to thepassenger. For similar reasons, it is important that hot particles donot reach the interior of the bag. The gasses used must have a lowtoxicity and for this reason carbon monoxide, nitrogen oxides, sulphurcompounds and the like are undesirable.

In some embodiments, deflation of the bag is obtained by using a fabricof controlled porosity since the entire phenomenon of passengerrestraint is kinetic. Thus, the bag rapidly inflates without asubstantial pressure gradient across the fabric and little gas flowstherethrough during the short time interval of inflation. Substantialpressures may be created in the bag as it restrains a passenger duringimpact and the energy of the passenger is dissipated over a period oftime which is controlled by the porosity of the fabric. Quite a bit ofgas is pushed out of the bag during this time. Subsequently the bagdeflates as gas flows through the fabric over a somewhat longer periodof time. Since the gas in such an embodiment is dissipated in thepassenger compartment of the automobile in close proximity to thepassenger being restrained, low temperature and low toxicity are ofappreciable importance. In addition, it is important that the gas berelatively free from smoke so as not to inhibit visibility by the driveror passengers and avoid any skin, eye or respiratory irritations thatmight arise from smoke particles. It is, therefore, desirable to providepyrotechnic compositions that burn to produce a large volume ofrelatively cool, non-toxic, smokefree gas in a very short time intervalfor inflating a passenger restraint bag.

The pyrotechnic composition must be sufficiently stable to sustain thetemperature, vibration and other environmental characteristics of anautomobile for a prolonged period without degradation of performance. Ina typical embodiment, about 265 grams of pyrotechnic composition may beemployed for inflating a five cubic foot bag. For this reason it isdesirable that the composition be relatively inexpensive.

BRIEF SUMMARY OF THE INVENTION Thus, in practice of this inventionaccording to a presently preferred embodiment, there is provided arelatively cool, non-toxic, substantially smoke free gas generatingcomposition comprising a mixture of an oxidizer compound containingoxygen and a metal and an oxygen bearing metal organic compound selectedso that a stoichiometric reaction therebetween yields gaseous carbondioxide and water vapor and a low melting, at least binary mixture ofmetal salts and a net heat of reaction less about 1,000 calories pergram. An excess of oxidizer over the stoichiometric proportion may beused to provide oxygen in the gas.

DESCRIPTION It is known that one can mix an oxidizer powder and areducing powder and ignite them to produce a mixture of carbon dioxideand water vapor for inflating a passenger restraint bag for anautomobile. Such powders are mixed and packed into a cavity in a gasgenerator. An electrical initiator is provided in the cavity for addinga sudden localized burst of energy for raising the temperature of thepyrotechnic mixture well above its ignition temperature. Once ignited,the entire mixture is typically consumed to produce carbon dioxideand/or water vapor which are directed to a passenger restraint bag forinflation. Some of the products of combustion are typically not gaseousand may remain in the gas generator or pass into the passenger restraintbag in the form of hot particles or as a smoke of finely dividedparticles.

The same general technique is employed in practice of this invention,except that compositions are provided with low net heat of reaction andwhich produce substantially smoke free gasses and a low melting slagthat deposits within the gas generator rather than being carried intothe passenger restraint bag.

Previously it has been proposed to employ carbohydrates and oxidizingagents in the form of powdered mixtures for deflagration to generategasses to inflate a fabric bag. The gasses produced are generally toohot and some type of cooling, such as endothermic chemicals ormechanical heat exchangers are used to assure that the gasses reachingthe inflatable bag are less than about 500F. which is presentlyconsidered to be an approximate maximum temperature for safe use in apassenger restraint system. Thus, for example, when a stoichiometricmixture of sucrose and potassium chlorate is reacted, there is a netheat of'reaction of about 1,080 calories per gram. Citric acid andpotassium chlorate reacted in a stoichiometric mixture have a net heatof reaction of about 912 calories per gram. When tartaric acid andpotassium perchlorate are reacted stoichiometrically, the net heat ofreaction is about 792 calories per gram which is one of the lowestcalorific outputs available from a suitable carbohydrate. Othercarbohydrates may be suitable from an energy point of view, butunsuitable because of low melting point, low decomposition temperature,high cost, toxicity, or the like.

The pyrotechnic mixtures utilized in practice of this invention overcomemany of the physical and chemical problems associated with the organicmaterials having low net heats of reaction. Substantial variations inproperties can be obtained in practice of this invention, which allowsconsiderable latitude in adjusting the calorific output of thepyrotechnic mixture to an optimum level for a particular application.

The oxidizers employed in practice of this invention are compoundsincluding oxygen and a metal, and are preferably selected from the classof the chlorates and perchlorates of sodium, potassium, lithium, barium,magnesium and calcium. In addition, the peroxides, superoxides andpermanganates of these metals may be suitable. Other oxidizers that aresuitable include chlorates of aluminum, cadmium, lead, and nickel;perchlorates of barium, lead, manganese and nickel; ammonium chlorate;ammonium perchlorate; cobaltous chlorate; cobaltous perchlorate; cupricchlorate; and ferrous perchlorate. Some of these are more hygroscopicthan the preferred materials and need protection from water vapor. Theammonium chlorate and ammonium perchlorate yield ammonium chloride uponreaction which also forms a low melting slag with metal salts. Thechlorates and perchlorates are particularly preferred, since thenon-gaseous product resulting from reaction is the chloride of themetal. As pointed out hereinafter, the combination of the metal chloridewith other metal containing reaction products, serves to make a lowmelting mixture which collects on the walls of the gas generator ratherthan being carried into the passenger restraint bag.

The pyrotechnic composition also includes an oxygen containing metalorganic compound which reacts with the oxidizer when the pyrotechnicmixture is ignited. As mentioned hereinafter, a substantial number ofoxygen bearing metal organic compounds are suitable. Particularlypreferred compounds include calcium formate, lithium formate, lithiumacid oxalate, potassium formate, potassium acid oxalate, sodium formate,and sodium acid oxalate. Reaction of any of these materials with theabove identified oxidizers yields a large volume of gas in the form ofcarbon dioxide and water vapor without unduly high caloric outputs.Thus, for example, the net heat of stoichiometric reaction of calciumformate and potassium perchlorate is only 426 calories per gram.Similarly, the net heat of stoichiometric reaction of sodium formate andpotassium perchlorate is only 220 calories per gram. A mixture of 67percent potassium formate and 33 percent potassium chlorate has a netheat of only 52 calories per gram. Approximately the same quantities ofgasare produced from equal weights of each of these pyrotechnic mixturesand the total caloric output of the reaction is quite low. By mixingvarious oxygen containing metal organic compounds in the pyrotechniccomposition a broad range of net heat outputs and low melting slags canbe provided.

The metal formates identified above are preferred in practice of thisinvention since the net heat of reaction with an oxidizer is quite lowand yet the reaction is sufficiently exothermic that once initiated itcontinues to completion. The net heat of a pyrotechnic composition canbe reduced by including a metal acid oxalate along with the metalformate. This reduces the temperature of the reaction products. Thegeneral reason for this can be understood by noting that the formula forthe metal formates is MH C O where M indicates any metal and it will beunderstood that suitable adjustments in the formula will be made for themetal valence. The formula for the metal acid oxalate, on the otherhand, is MHC O By selecting suitable mixtures of metal formate, andmetal acid oxalate, a broad range of net heats of reaction can beobtained in order to adjust the temperature of the reaction products andthe rapidity of the combustion reaction. Exemplary of the low net heatsof reaction obtainable in practice of this invention include 27 percentpotassium chlorate and 73 percent barium formate with a net heat ofreaction of about 223 calories per gram. When 78 percent lead formate isreacted with 22 percent potassium chlorate a net heat of about 300calories per gram is obtained. Zinc formate and potassium chlorate inthe stoichiometric proportion yield a net heat of about 506 calories pergram. With such a variety available, almost any desired net heat ofreaction is obtainable with suitable mixtures of reactants.

The metal acid oxalates are useful since the caloric output is low andthe rate of reaction may be sufficient to be self-sustaining. From allof these materials, nontoxic gases are obtained.

Although the formates, and acid oxalates of sodium, potassium, lithiumand calcium are particularly preferred in practice of this invention, alarger group of materials has also been found suitable for practice ofthis invention. Thus the following oxygen bearing metal organiccompounds are found to be suitable components of a pyrotechnic mixture:aluminum acetate, aluminum citrate, barium formate, barium acetate,barium citrate, barium butyrate, barium malonate, barium propionate,barium succinate, cadmium formate, cadmium acetate, cadmium lactate,calcium formate, calcium acetate, calcium citrate, calcium tartrate,calcium lactate, calcium benzonate, calcium salicylate, cerous acetate,cesium acid tartrate, chromic acetate, cobaltous acetate, columbium acidoxalate, cupric formate, cupric acetate, dysprosium acetate, erbiumacetate, ferric acetate, ferrous formate, ferrous acetate, ferroustartrate, ferrous lactate, gadolinium acetate, lead formate, leadacetate, lithium formate, lithium acetate, lithium citrate, lithium acidoxalate, lithium benzoate, lithium salicylate, magnesium formate,magnesium acetate, magnesium citrate, magnesium tartrate, magnesiumbenzoate, manganese formate, manganese acetate, manganese lactate,manganese benzoate, nickel formate, nickel acetate, potassium formate,potassium acetate, potassium acid acetate, potassium citrate, potassiumtartrate, potassium acid tartrate, potassium acid oxalate, potassiumbenzoate, potassium acid phthalate, samarium formate, samarium acetate,silver acetate, silver citrate, silver tartrate, sodium formate, sodiumacetate, sodium citrate, sodium tartrate, sodium acid tartrate, sodiumacid oxalate, sodium salicylate, sodium methylate, strontium formate,strontium acetate, strontium tartrate, strontium lactate, strontiumsalicylate, thallium acetate, ytterbium acetate, zinc formate, and zincacetate.

Some of these materials are less suitable than the particularlypreferred group because of cost or somewhat higher net heat of reactionor formation of a somewhat higher melting point binary mixture afterreaction with the oxidizer. In some cases, despite these factors, thematerials are quite useful in combination with the oxygen bearing metalorganic compounds, particularly preferred in the pyrotechniccomposition.

Materials in this larger group of oxygen bearing metal organic compoundscan be used in practice of this invention, either alone or in a varietyof mixtures thereof. Such mixtures are of considerable assistance intailoring the pyrotechnic composition to particular performancecriteria, such as reaction time, net heat of reaction, resultant gascomposition and temperature and melting point of the mixture ofnon-gaseous products.

An intermediate group of oxygen containing metal organic compounds hasbeen identified as suitable for practice of this invention. Thesematerials combine readily with the above identified oxidizers and givegood gas volumes without high net heat output or excess smoke. Good lowmelting slags are produced. This intermediate group of compoundscomprises: aluminum citrate, barium formate, barium citrate, calciumformate, calcium citrate, calcium acid tartrate, chromic acetate, cupricformate, ferrous tartrate, lithium formate, lithium acid oxalate,lithium citrate, magnesium formate, magnesium citrate, magnesiumtartrate, manganese formate, nickel formate, potassium formate,potassium acid oxalate, potassium citrate, potassium tartrate, potassiumacid tartrate, silver citrate, silver tartrate, sodium formate, sodiumacid oxalate, sodium citrate, sodium tartrate, sodium acid tartrate,strontium formate, strontium tartrate, zinc forrnate, and zinc oxalate.

These materials may be used alone or in combination with other preferredoxygen bearing metal organic compounds for applications requiring aparticular net heat of reaction or unique combination of reactionproducts.

The materials listed above are exemplary of compounds including a singlemetal rather than a plurality of metals and it will be understood thatthere are additional compounds suitable for practice of this inventionhaving two metal ions in the oxygen bearing organic compound. Thus, forexample, sodium potassium tartrate is well suited to practice of thisinvention. Many other oxygen bearing metal organic compounds having morethan one metal ion in the molecule will be apparent. Such binary metalorganic compounds can be particularly useful in combination with anoxidizer having still a third metal in order to produce ternarynongaseous reaction product mixtures having quite low melting points.

It is preferred that the proportion of oxidizer compound and oxygenbearing metal organic compound be present in the pyrotechnic compositionin a proportion that reacts to produce gasses consisting primarily ofcarbon dioxide and water vapor, primarily to avoid formation of carbonmonoxide which is toxic. Even though carbon dioxide and water are nottoxic, they can displace oxygen from the local environment and it istherefore often desirable to have a proportion of oxygen in the reactionproduct as well. This is readily accomplished by increasing theproportion of oxidizer compound above the stoichiometric proportion.Thus, for example, when two moles of sodium formate are reacted with onemole of potassium perchlorate, the reaction products include two molesof carbon dioxide and one mole each of water vapor and oxygen. The netheat of reaction is only 164 calories per gram and percent of the gas isoxygen. If larger proportions of oxygen or pyrotechnic compositions withlower caloric outputs are desired, still higher excesses of oxidizerabove stoichiometry may be used. This is done at the expense of burningrate of the pyrotechnic; however, this can ordinarily be compensated forby variation in the geometry of the gas generator and increase of theenergy of the electric initiator to achieve an optimum burning rate.Generally speaking, it is preferred that the excess of oxidizer over thestoichiometric proportion be no more than about percent by weight of thetotal pyrotechnic mixture, so that special means are not required foradjusting burning rate or the like and the compositions are moreuniversally useful. It is preferred that the oxidizer compound bepresent in a proportion less than about 30 percent over thestoichiometric proportion, since the volume of gas obtained by reactionis greater than the volume of gas obtained by mere decomposition andthere is no substantial benefit in further increasing the oxygen contentof the reaction products.

Since some of the reactions between the inorganic oxidizers and oxygenbearing metal organic compounds have very low net heats of reaction, itis sometimes found that the rate of reaction is rather slow for asuccessful automobile passenger restraint system. The rate of reactioncan be enhanced by energetic initiation of the combustion of the powdermixture. Such initiation of the reaction can be accomplished by avariety of chemical reactions that generate high temperatures. Many suchinitiators, however, introduce toxic gases and should be avoided. It is,therefore, particularly preferred to initiate the reaction in the gasgenerator by a deflagration mixture formed of the powders of aninorganic oxidizer compound and an oxygen bearing organic fuel.Generally speaking, the oxidizer compounds hereinabove identified aresuitable for the initiation mixture. In particular, the chlorates andperchlorates of the alkali metals are preferred.

The oxygen bearing organic fuel is one having a formula C H O where x, yand z are integers. The powder should have an average particle size lessthan about 25 microns and be solid at all temperatures below about F inorder to be satisfactory for an automobile passenger restraint system.Suitable organic fuels can be selected from the group consisting ofsucrose, starch, cellulose, dextrose, dextrin, fructose, lactose,ascorbic acid, benzoic acid, maltose monohydrate, mannitol,mannoheptose, mannoheptose monohydrate, oxalic acid, propanediolic acidand glyoxylic acid. Preferably the oxidizer and fuel are mixed instoichiometric proportions for producing principally carbon dioxide andwater vapor as the gaseous products, since this yields a maximuminitiation energy. In a typical embodiment for a 500 gram main charge,as hereinabove described, an initiator mixture of about 25 grams issufficient. Many other high energy initiation techniques will beapparent to one skilled in the art.

As suggested above, a reaction of important significance to the overallperformance of the gas generator system for a passenger restraint bag,involves the nongaseous products of the reaction between the oxidizercompound and the oxygen bearing metal organic compound. The reactiontypically produces a metal oxide and when the chlorates or perchloratesare used, a metal chloride. Such binary mixtures of metal salts havemelting points that are below the melting point of either of the metalsalts alone. The binary mixtures of metal oxide and metal chloride, haveparticularly low melting points and combinations of oxidizer and metalorganic compound yielding such a mixture upon reaction are preferred. Ifoxidizers are used that do not yield a metal chloride, it is preferredthat different metal ions be present in at least part of the oxidizerand metal organic. This assures at least a binary mixture of metal saltsfor getting a melting point lower than either metal salt alone. Ternaryor more complex mixtures of metal salts may be used for low melting.

The melting point of the non-gaseous reaction products is ofconsiderable importance in an automobile passenger restraint system inkeeping the reaction products from entering the passenger restraint bag.Previously, when a metal oxide or metal chloride or the like wasproduced from a pyrotechnic composition, the temperature of the productwas such that most of it was in solid form which passed int-o thepassenger restraint bag, either as hot particles or in a sufficientlyfinely divided form to appear as a smoke. Neither of these issatisfactory.

With low melting mixtures as provided in practice of this invention, thenon-gaseous products apparently remain in liquid form for a longerperiod and can solidify on the cooler walls of the gas generator andsimilar solid surfaces. Thus, it is found that instead of producing asmoke in the passenger restraint bag, a spongy mass of a ceramic likematerial forms in the gas generator and very little, if any, smoke goesto the bag.

One approach to inhibiting hot particles from entering the passengerrestraint bag has been to pass the reaction products through a porousmember en route to the bag. It is sometimes found that the particles ofnongaseous reaction product accumulate in the pores and tend to plug upsuch a filter. When a low melting mixture of non-gaseous reactionproduct is directed against such a filter, a spongy mass collects whichis in itself porous and little deleterious plugging of porous filters isnoted.

In addition to inhibiting the presence of smoke and hot particles in thepassenger restraint bag, the low melting mixture of nongaseous reactionproducts accounts for a substantial proportion of the reaction heat.Since these products collect on the walls of the gas generator, much ofthe heat remains in the gas generator and is not conveyed into thepassenger restraint bag. This enhanced retention of heat in the gasgenerator itself permits the use of pyrotechnic mixtures having somewhathigher net heats of reaction than could be tolerated if the non-gaseousreaction products were largely passed to the passenger restraint bag ashas been the case previously.

In the simplest embodiment, the low melting mixture of non-gaseousreaction products is a binary mixture such as, for example, calciumoxide and potassium chloride, sodium oxide and sodium chloride, lithiumchloride and potassium oxide, or sodium oxide and potassium chloride. Asis well known in the ceramic arts, ternary mixtures non-gaseous reactionproducts such as, for example, nickel oxide, potassium oxide and sodiumchloride may be lower than the melting point obtainable with any of thethree possible binary mixtures. Thus, in practice of this invention, themetal containing oxidizer and the oxygen bearing metal organic compoundare selected so that the non-gaseous reaction products form at least abinary mixture of metal salts having a melting point less than themelting point of any of the metal salts formed by the reaction. Ifdesired, ternary, quaternary or other mixtures of metal salts may becreated for significant melting point reductions.

Preferably the pyrotechnic mixture comprises an intimate combination ofoxidizer compound powder and oxygen bearing metal organic powder. Thishas the advantage of not requiring any binders or cements which couldinterfere with reaction or introduce toxicity in the combination. Suchpowders are preferably compacted at light pressures, such as forexample, 50 to 100 psi although substantially higher compaction pressures can be employed without significantly affecting the rate ofreaction. Preferably the compaction pressure is less than about 5,000psi, since pressures in that order may alter the burning characteristicsof the pyrotechnic mixture. A compacted powder is less affected byvibration like that encountered in a passenger restraint system in anautomobile, than are pellets or grains which may break up and thereforechange their burning characteristics. If desired, the burning rate ofthe powder can be controlled by the compaction pressure and it is alsosusceptible to packing into gas generators of non-uniform cross section,which may be employed for controlling the burning rate. Preferably theparticle size of the metal organic compound and the oxidizer is lessthan about 25 microns in order to obtain substantially complete reactionwithout a residue of unburned materials or undue production of hotreaction particles. When the particle size of both the metal organicpowder and the oxidizer powder is less than about 5 microns,substantially complete reaction therebetween is virtually certain andunintentional formation of carbon monoxide thereby inhibited.

Particularly preferred combinations of metal containing oxidizer powderand oxygen bearing metal organic compound forming a pyrotechniccomposition include calcium formate in the range of from about 35 to 60percent by weight and potassium chlorate in the range of from 40 topercent by weight; calcium formate in the range of from about 40 to 65percent by weight and potassium perchlorate in the range of from about35 to 60 percent by weight; sodium formate in the range of from about 35to 60 percent by weight and potassium chlorate in the range of fromabout 40 to 65 percent by weight; sodium formate in the range of fromabout 40 to 65 percent by weight and potassium perchlorate in the rangeof from about 35 to 60 percent by weight; nickel formate in the range offrom about 50 to 69 percent by weight and potassium chlorate in therange of from about 31 to 50 percent by weight; and nickel formate inthe range of from about 65 to 72 percent by weight and potassiumperchlorate in the range of from about 28 to 35 percent by weight.

Particularly preferred compositions comprise potassium chlorate in aproportion of about 65 percent and either sodium formate or calciumformate in a proportion of about 35 percent by weight. The compositionincluding calcium formate is particularly well suited for inflating apassenger restraint bag deployed from the center of a steering wheel inan automobile. The reaction is relatively rapid and the restraint bagcan be completely inflated in about 25 milliseconds. The sodium formatebearing composition is particularly preferrerd for the right frontpassenger seat of an automobile. The reaction is somewhat slower thanthe one between calcium formate and potassium chlorate and the passengerrestraint bag is completely inflated in about 50 to 60 milliseconds.

Other preferred compositions include about 30 percent calcium formate,30 percent potassium acid oxalate and 40 percent potassium chloratewhich reacts with a net heat of about 200 calories per gram. Theresultant slag is a ternary mixture of potassium chloride, potassiumoxide and calcium oxide which has a melting point substantially below1,400F. Another preferred composition comprises about 30 percent sodiumfor mate, 30 percent potassium acid oxalate and 40 percent potassiumchlorate. The ternary slag produced by such reaction has a melting pointin the range of about 800 to 1,000F. Another suitable composition havinga ternary slag and low net heat of reaction comprises about 30 percentcalcium oxalate, 30 percent formate and 40 percent potassium chlorate.

A large number of pyrotechnic compositions in accordance with principlesof this invention have been made and tested by igniting them in a gasgenerator connected to an inflatable passenger restraint bag. In varioustests performed, time of bag inflation, pressure in the gas generator,volume of gas produced, temperature of gas in the bag, gas composition,smoke formation and the like have been measured. In addition, thepresence or absence of hot particles in the inflation bag andcharacteristics of deposits in the gas generator have been observed.Other tests include calorimetry, bench tests of burn rate, gasproduction tests, and the like with an actual bag connected to the gasgenerator. Among the many tests performed, the following pyro techniccompositions have performed satisfactorily in tests evaluatingperformance of this invention:

1. Calcium formate 60%, potassium chlorate 40%;

2. Calcium formate 45%, potassium chlorate 55%;

3. Calcium formate 35%, potassium chlorate 65%;

4. Calcium formate 65%, potassium perchlorate 35%;

5. Calcium formate 50%; potassium perchlorate 50%;

6. Calcium formate 40%, potassium perchlorate 60%;

7. Sodium formate 60%, potassium chlorate 40%;

8. Sodium formate 45%, potassium chlorate 55%;

9. Sodium formate 35%, potassium chlorate 65%;

10. Sodium formate 65%, potassium perchlorate 35%;

11. Sodium formate 50%, potassium perchlorate 50%;

12. Sodium formate 40%, potassium perchlorate 60%;

13. Nickel formate 69%, potassium chlorate 31%;

14. Nickel formate 50%, potassium chlorate 50%;

15. Nickel formate 72%, potassium perchlorate 28%;

16. Nickel formate 65%, potassium perchlorate 35%;

17. Calcium formate 30%, potassium acid oxalate 30%,

potassium chlorate 40%;

18. Sodium formate 30%, potassium acid oxalate 30%,

potassium chlorate 40%;

19. Calcium formate 30%, calcium oxalate 30%, potassium chlorate 40%;

20. Manganese formate 64%, potassium chlorate 36%;

21. Potassium formate 67%, potassium chlorate 44%;

22. Lithium formate 56%, potassium chlorate 44%;

23. Magnesium formate 58%, potassium chlorate 42%;

24. Ammonium formate 60%, potassium chlorate 40%;

25. Barium formate 73%, potassium chlorate 27%;

26. Cupric formate 65%, potassium chlorate 35%;

27. Ferrous formate 68%, potassium chlorate 32%;

28. Lead formate 78%, potassium chlorate 22%; and

29. Zinc formate 65%, potassium chlorate 35%.

Although numerous embodiments of this invention have been set forthherein, many additional modifications and variations will be apparent toone skilled in the art. It is therefore to be understood that within thescope of the appended claims the invention may be practiced otherwisethan as specifically described.

What is claimed is:

1. A pyrotechnic powder composition consisting essentially of a mixtureof one or more oxidizer compounds containing oxygen and a metal selectedfrom the group consisting of sodium, potassium, lithium, barium,magnesium and calcium, and one or more oxygen bearing metal organiccompounds selected such that a stoichiometric reaction between theoxidizer and the metal organic compound yields gaseous products selectedfrom the class consisting of carbon dioxide and water vapor andnon-gaseous products of at least a binary mixture of metal salts havinga melting point substantially below the melting point of any of theresultant metal salts and having a net heat of reaction less than about1,000 calories per gram, the proportion of oxidizer compound to metalorganic compound being no less than the stoichiometric proportion.

2. A pyrotechnic powder composition as defined in claim 1 wherein theoxidizer compound is selected from the group consisting of chlorates andperchlorates.

3. A pyrotechnic powder composition as defined in claim 2 wherein themetal organic compound is selected from the group consisting of metalformates, and metal acid oxalates.

4. A pyrotechnic powder composition comprising a mixture of an oxidizercompound containing oxygen and a metal selected from the groupconsisting of sodium, potassium, lithium, barium, magnesium and calcium,and a metal organic compound selected from the class consisting of metalacid oxalates and metal formates.

5. A pyrotechnic powder composition as defined in claim 4 wherein themetal organic compound is selected from the group consisting of calciumformate, lithium formate, lithium acid oxalate, potassium formate,potassium acid oxalate, sodium formate, and sodium acid oxalate; and theoxidizer compound is se' lected from the group consisting of thechlorates and perchlorates.

6. A pyrotechnic powder composition comprising a mixture of an oxidizercompound selected from the group consisting of sodium chlorate, sodiumperchlorate, potassium chlorate, potassium perchlorate, lithiumchlorate, lithium perchlorate, barium chlorate, barium perchlorate,magnesium chlorate, magnesium perchlorate, calcium chlorate, calciumperchlorate, aluminum chlorate, ammonium chlorate, ammonium perchlorate,cadmium chlorate, cobaltous chlorate, cobaltous perchlorate, cupricchlorate, ferrous perchlorate, lead chlorate, lead perchlorate,manganese perchlorate, nickel chlorate and nickel perchlorate; and anoxygen bearing metal organic compound selected from the group consistingof aluminum acetate, aluminum citrate, barium formate, barium acetate,barium citrate, barium butyrate, barium 'malonate, barium propionate,barium succinate, cadmium formate, cadmium acetate, cadmium lactate,calcium formate, calcium acetate, calcium citrate, calcium tartrate,calcium lactate, calcium benzoate, calcium salicylate, cerous acetate,cesium acid tartrate, chromic acetate, cobaltous acetate, columbium acidoxalate, cupric formate, cupric acetate, dysprosium acetate, erbiumacetate, ferric acetate, ferrous formate, ferrous acetate, ferroustartrate, ferrous lactate, gadolinium acetate, lead formate, leadacetate, lithium formate, lithium acetate, lithium citrate, lithium acidoxalate, lithium benzoate, lithium salicylate, magnesium formate,magnesium acetate, magnesium citrate, magnesium tartrate, magnesiumbenzoate, manganese formate, manganese acetate, manganese lactate,manganese benzoate, mercuric acetate, nickel formate, nickel acetate,potassium formate, potassium acetate, potassium acid acetate, potassiumcitrate, potassium tartrate, potassium acid tartrate, potassium acidoxalate, potassium benzoate, potassium acid phthalate, Samarium formate,Samarium acetate, silver acetate, silver citrate, silver tartrate,sodium formate, sodium acetate, sodium citrate, sodium tartrate, sodiumacid tartrate, sodium acid oxalate, sodium salicylate, sodium methylate,strontium fonnate, strontium acetate, strontium tartrate, strontiumlactate, strontium salicylate, thallium acetate, ytterbium acetate, zincformate, zinc acetate and zinc oxalate.

7. A pyrotechnic powder composition as defined in claim 6 wherein theoxygen bearing metal organic compound is selected from the groupconsisting of aluminum citrate, barium formate, barium citrate, calciumformate, calcium citrate, calcium acid tartrate, chromic acetate, cupricformate, ferrous tartrate, lithium formate, lithium acid oxalate,lithium citrate, magnesium formate, magnesium citrate, magnesiumtartrate, manganese formate, nickel formate, potassium formate,potassium acid oxalate, potassium citrate, potassium tartrate, potassiumacid tartrate, silver citrate, silver tartrate, sodium formate, sodiumacid oxalate, sodium citrate, sodium tartrate, sodium acid tartrate,strontium formate, strontium tartrate and zinc formate.

8. A pyrotechnic powder composition as defined in claim 7 wherein theoxidizer powder is selected from the group consisting of the chloratesand perchlorates of sodium, potassium, lithium, barium, magnesium andcalcium.

9. A pyrotechnic powder composition as defined in claim 6 wherein theoxygen bearing metal organic compound is selected from the groupconsisting of calcium formate, lithium formate, lithium acid oxalate,potassium formate, potassium acid oxalate, sodium formate, and sodiumacid oxalate.

10. A pyrotechnic powder composition as defined in claim 9 wherein theoxidizer powder is selected from the group consisting of the chloratesand perchlorates of sodium, potassium, lithium, barium, magnesium andcalcium.

1 l. A pyrotechnic powder composition as defined in claim 6 wherein theoxidizer powder is selected from the group consisting of the chloratesand perchlorates of sodium, potassium, lithium, barium, magnesium andcalcium.

12. A pyrotechnic powder composition as defined in claim 6 wherein themixture is selected from the group consisting of calcium formate in therange of from about 35 to percent by weight and potassium chlorate inthe range of from about 40 to percent by weight; calcium formate in therange of from about 40 to 65 percent by weight and potassium perchloratein the range of from about 35 to 60 percent by weight; sodium formate inthe range of from about 35 to 60 percent by weight and potassiumchlorate in the range of from about 40 to 65 percent by weight; sodiumformate in the range of from about 40 to 65 percent by weight andpotassium perchlorate in the range of from about 35 to 60 percent byweight; nickel formate in the range of from about 50 to 69 percent byweight and potassium chlorate in the range of from about 31 to 50 percent by weight; nickel formate in the range of from about 65 to 72percent by weight and potassium perchlorate in the range of from about28 to 35 percent by weight; calcium formate in a proportion of about 30percent by weight, potassium acid oxalate in a proportion of about 30percent by weight and potassium chlorate in a proportion of about 40percent by weight; sodium formate in a proportion of about 30 percent byweight, potassium acid oxalate in a proportion of about 30 percent byweight and potassium chlorate in a proportion of about 40 percent byweight; and calcium formate in a proportion of about 30 percent byweight, calcium oxalate in a proportion of about 30 percent by weightand potassium chlorate in a proportion of about 40 percent by weight.

13. A pyrotechnic powder composition as defined in claim 6 wherein theoxidizer compound comprises about 65 percent by weight of potassiumchlorate and the metal organic compound comprises about 35 percent byweight of calcium formate.

14. A pyrotechnic powder composition as defined in claim 6 wherein theoxidizer compound comprises about 65 percent by weight of potassiumchlorate and the metal organic compound comprises about 35 percent byweight of sodium formate.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTIONPATENT NO. I 3 ,9l0,805

DATED I October 7, 1975 |NVENTOR(5) 3 Vincent 0. Catanzarite It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 8, Line 61, after "percent" and before "formate" insert calciumSigned and Scaled this seventeenth Day Of February 1976 [SEAL] Attest:

RUTH C. MASON C. MARSHALL DANN Arresting Ojfr'ter (ummissimreroj'larents and Trademarks UNITED STATES PATENT AND TRADEMARK OFFICECERTIFICATE OF CORRECTION PATENT NO. 3,910,805

DATED I October 7, 1975 |NVENTOR(5) 1 Vincent 0. Catanzarite It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 8, Line 61, after "percent" and before "formate" insert calciumSigned and Sealed this seventeenth Day Of February 1976 [SEAL] Attest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner ofParenrsand Trademarks

1. A PYROTECHNIC POWDER COMPOSITION CONSISTING ESSENTIALLY OF A MIXTUREOF ONE OR MORE OXIDIZER COMPOUND CONTAINING OXYGEN AND A METAL SELECTEDFROM THE GROUP CONSISTING OF SODIUM, PATASSIUM, LITHIUM, BARIUM,MAGNESIUM AND CALCIUM, AND ONE OR MORE OXYGEN BEARING METAL ORGANICCOMPOUNDS SELECTED SUCH THAT A STOICHIOMETRIC REACTION BETWEEN THEOXIDIZER AND THE METAL ORGANIC COMPOUND YIELDS GASEOUS PRODUCTS SELECTEDFROM THE CLASS CONSISING OF CARBON DIOXIDE AND WATER VAPOR ANDNON-GASEOUS PRODUCTS AT LEAST A BINARY MIXTURE OF METAL SALTS HAVING AMELTING POINT SUBSTANTIALLY BELOW THE MELTING POINS OF ANY OF THERESULTANT METAL SALTS AND HAVING A NET HEAT OF REACTION LESS THAN ABOUT1,000 CALORIES PER GRAM THE PROPORTION OF OXIDIZER COMPOUND TO METALORGANIC COMPOUND BEGIN NO LESS THAN THE STOCHIOMETRIC PROPORATION.
 2. Apyrotechnic powder composition as defined in claim 1 wherein theoxidizer compound is selected from the group consisting of chlorates andperchlorates.
 3. A pyrotechnic powder composition as defined in claim 2wherein the metal organic compound is selected from the group consistingof metal formates, and metal acid oxalates.
 4. A pyrotechnic powdercomposition comprising a mixture of an oxidizer compound containingoxygen and a metal selected from the group consisting of sodium,potassium, lithium, barium, magnesium and calcium, and a metal organiccompound selected from the class consisting of metal acid oxalates andmetal formates.
 5. A pyrotechnic powder composition as defined in claim4 wherein the metal organic compound is selected from the groupconsisting of calcium formate, lithium formate, lithium acid oxalate,potassium formate, potassium acid oxalate, sodium formate, and sodiumacid oxalate; and the oxidizer compound is selected from the groupconsisting of the chlorates and perchlorates.
 6. A pyrotechnic powdercomposition comprising a mixture of an oxidizer compound selected fromthe group consisting of sodium chlorate, sodium perchlorate, potassiumchlorate, potassium perchlorate, lithium chlorate, lithium perchlorate,barium chlorate, barium perchlorate, magnesium chlorate, magnesiumperchlorate, calcium chlorate, calcium perchlorate, aluminum chlorate,ammonium chlorate, ammonium perchlorate, cadmium chlorate, cobaltouschlorate, cobaltous perchlorate, cupric chlorate, ferrous perchlorate,lead chlorate, lead perchlorate, manganese perchlorate, nickel chlorateand nickel perchlorate; and an oxygen bearing metal organic compoundselected from the group consisting of aluminum acetate, aluminumcitrate, barium formate, barium acetate, barium citrate, bariumbutyrate, barium malonate, barium propionate, barium succinate, cadmiumformate, cadmium acetate, cadmium lactate, calcium formate, calciumacetate, calcium citrate, calcium tartrate, calcium lactate, calciumbenzoate, calcium salicylate, cerous acetate, cesium acid tartrate,chromic acetate, cobaltous acetate, columbium acid oxalate, cupricformate, cupric acetate, dysprosium acetate, erbium acetate, ferricacetate, ferrous formate, ferrous acetate, ferrous tartrate, ferrouslactate, gadolinium acetate, lead formate, lead acetate, lithiumformate, lithium aceTate, lithium citrate, lithium acid oxalate, lithiumbenzoate, lithium salicylate, magnesium formate, magnesium acetate,magnesium citrate, magnesium tartrate, magnesium benzoate, manganeseformate, manganese acetate, manganese lactate, manganese benzoate,mercuric acetate, nickel formate, nickel acetate, potassium formate,potassium acetate, potassium acid acetate, potassium citrate, potassiumtartrate, potassium acid tartrate, potassium acid oxalate, potassiumbenzoate, potassium acid phthalate, samarium formate, samarium acetate,silver acetate, silver citrate, silver tartrate, sodium formate, sodiumacetate, sodium citrate, sodium tartrate, sodium acid tartrate, sodiumacid oxalate, sodium salicylate, sodium methylate, strontium formate,strontium acetate, strontium tartrate, strontium lactate, strontiumsalicylate, thallium acetate, ytterbium acetate, zinc formate, zincacetate and zinc oxalate.
 7. A pyrotechnic powder composition as definedin claim 6 wherein the oxygen bearing metal organic compound is selectedfrom the group consisting of aluminum citrate, barium formate, bariumcitrate, calcium formate, calcium citrate, calcium acid tartrate,chromic acetate, cupric formate, ferrous tartrate, lithium formate,lithium acid oxalate, lithium citrate, magnesium formate, magnesiumcitrate, magnesium tartrate, manganese formate, nickel formate,potassium formate, potassium acid oxalate, potassium citrate, potassiumtartrate, potassium acid tartrate, silver citrate, silver tartrate,sodium formate, sodium acid oxalate, sodium citrate, sodium tartrate,sodium acid tartrate, strontium formate, strontium tartrate and zincformate.
 8. A pyrotechnic powder composition as defined in claim 7wherein the oxidizer powder is selected from the group consisting of thechlorates and perchlorates of sodium, potassium, lithium, barium,magnesium and calcium.
 9. A pyrotechnic powder composition as defined inclaim 6 wherein the oxygen bearing metal organic compound is selectedfrom the group consisting of calcium formate, lithium formate, lithiumacid oxalate, potassium formate, potassium acid oxalate, sodium formate,and sodium acid oxalate.
 10. A pyrotechnic powder composition as definedin claim 9 wherein the oxidizer powder is selected from the groupconsisting of the chlorates and perchlorates of sodium, potassium,lithium, barium, magnesium and calcium.
 11. A pyrotechnic powdercomposition as defined in claim 6 wherein the oxidizer powder isselected from the group consisting of the chlorates and perchlorates ofsodium, potassium, lithium, barium, magnesium and calcium.
 12. Apyrotechnic powder composition as defined in claim 6 wherein the mixtureis selected from the group consisting of calcium formate in the range offrom about 35 to 60 percent by weight and potassium chlorate in therange of from about 40 to 65 percent by weight; calcium formate in therange of from about 40 to 65 percent by weight and potassium perchloratein the range of from about 35 to 60 percent by weight; sodium formate inthe range of from about 35 to 60 percent by weight and potassiumchlorate in the range of from about 40 to 65 percent by weight; sodiumformate in the range of from about 40 to 65 percent by weight andpotassium perchlorate in the range of from about 35 to 60 percent byweight; nickel formate in the range of from about 50 to 69 percent byweight and potassium chlorate in the range of from about 31 to 50percent by weight; nickel formate in the range of from about 65 to 72percent by weight and potassium perchlorate in the range of from about28 to 35 percent by weight; calcium formate in a proportion of about 30percent by weight, potassium acid oxalate in a proportion of about 30percent by weight and potassium chlorate in a proportion of about 40percent by weight; sodium formate in a proportion of about 30 percent byweight, potassium acid oxalate in a proportion of about 30 percent byweight and potassium chlorate in a proportion of about 40 percent byweight; and calcium formate in a proportion of about 30 percent byweight, calcium oxalate in a proportion of about 30 percent by weightand potassium chlorate in a proportion of about 40 percent by weight.13. A pyrotechnic powder composition as defined in claim 6 wherein theoxidizer compound comprises about 65 percent by weight of potassiumchlorate and the metal organic compound comprises about 35 percent byweight of calcium formate.
 14. A pyrotechnic powder composition asdefined in claim 6 wherein the oxidizer compound comprises about 65percent by weight of potassium chlorate and the metal organic compoundcomprises about 35 percent by weight of sodium formate.